I have a very rare hovercraft that I always wanted to convert to brushless but never got around to. It probably will even be fine with the brushed motors if using LiPos as the weight savings will be immense.
Here is a link that gives you an idea of the performance (I'm sure that is with heavy NiCads) that I found on the web:http://www.tamiyaclub.com/showroom_model.asp?cid=26407

You can also download a video of that model (again, not mine) here
I just posted actual pics. This is so very rare it's not even funny I am asking $150 picked up in SoCal (O.C.) or you pay actual shipping.